1. Technical Field
The present invention relates to an optical waveguide component formed with an optical waveguide adapted to be connected to an optical fiber, and more particularly, to an optical waveguide component which facilitates an accurate connection between an optical waveguide formed in the waveguide component and an optical fiber formed in an optical connector plug.
2. Related Art
Optical waveguide components formed with optical waveguides are employed to construct an optical communication system. In general, an optical waveguide is connected at each of opposite end faces with a single fiber or multi fibers. A technical art for connecting an optical waveguide with optical fibers is known, in which an optical waveguide component and optical fibers are moved three-dimensionally relatively to one another and fixed together at their relative positions where a light beam output from an output-side optical fiber provides a maximum power when a light beam is input to an input-side optical fiber. However, the aforesaid alignment adjusting operation in this technique requires much time and labor.
To eliminate such an adjustment, another connecting technique is known, in which an optical waveguide component is connected to an optical connector plug with use of guide pins that are fitted into guide pin holes formed in both the waveguide component and the connector plug. According to this technique, an optical fiber connected in advance with the connector plug can be connected to an optical waveguide formed in the waveguide component, without the need of making a particular alignment operation.
In FIGS. 1-5, an optical waveguide component of this kind proposed by the present applicant is exemplarily shown. This optical waveguide component comprises an optical waveguide chip (waveguide component body) 1 formed with an optical waveguide pattern (more generally, one or more optical waveguides), and connecting end members 2, 3 respectively mounted on opposite ends of the waveguide chip 1. By connecting the connecting end members 2, 3 to optical connector plugs 23 to which respective one end portions of optical fiber ribbons 21 are connected, optical fibers of the optical fiber ribbons 21 are connected to the optical waveguide pattern of the waveguide component.
As best shown in FIG. 2, the waveguide chip 1 comprises an elongated plate-like substrate 4 on which a clad 5 and a core 6 embedded therein are formed longitudinally of the waveguide chip. A pair of positioning guides 9 are formed in an upper face of the waveguide chip 1 longitudinally thereof at locations just inside lateral edge portions 8a, 8b of the clad 5.
Each of the connecting end members 2, 3 is formed with a recess 16 in which a corresponding end portion of the waveguide chip 1 is closely received. As best shown in FIG. 4, two pairs of projecting strips are formed in a horizontal inner face 11 of the connecting end member at two corner portions of the recess 16. Two projecting strips forming each projecting-strip pair are laterally adjacent to each other and are each formed into a triangular shape in transverse cross section, thereby forming a positioning guide groove 14 or 15 therebetween.
By inserting one end portion of the waveguide chip 1 into the recess of the connecting end member 2 as shown in FIG. 4, the positioning guides 9 are fitted into the positioning guide grooves 14, whereby the one end portion of the waveguide chip 1 is positioned in the recess 16 and fixed to the connecting end member 2 in a state that a connecting end face 25a of the waveguide chip is exposed, by means of adhesive applied to the horizontal inner face 11 and vertical inner faces of the connecting end member 2. Similarly, another end portion of the waveguide chip 1 is fixed in the recess 16 of the connecting end member 3, with its connecting end face 25b exposed.
Next, opposite end portions of a protective member 18 are engaged with stepped portions 27 formed in outer faces of inner end portions of the connecting end members 2 and 3, whereby the assemblage of the waveguide component is completed (FIG. 1). Between the connecting end members 2 and 3, the upper and side faces of the waveguide chip 1 are surrounded and protected by the protective member 18.
Prior to connecting optical fiber ribbons 21 (FIG. 5) and the waveguide component, tip end portions of the optical fiber ribbons 21 are connected to optical connector plugs 23, and respective one halves of guide pins 19 and 20 are inserted into guide-pin fitting holes 12 and 13 formed in each connecting end member 2 or 3.
After the connector plugs 23 are disposed such that their tip end faces 30 oppose the tip end faces 28, 29 of the connecting end members 2, 3 and that through holes 22 formed in the connector plugs 23 are aligned with the guide pins 19, 20 projecting from the tip end faces of the connecting end members, the tip end portions of the guide pins 19, 20 of the connecting end members are inserted into the through holes 22 of the connector plugs 23, and the connector plugs 23 are moved toward the connecting end members until their connecting end faces 30 are brought in contact with the tip end faces 28, 29 of the connecting end members 2, 3. The connecting end faces 30 of the connecting end members and the tip end faces of the optical fiber ribbons 21 are disposed to oppose the tip end faces 28, 29 of the connecting end members and the connecting end faces 25a, 25b of the waveguide chip 1, respectively, through refractive-index matching agent applied in advance thereto.
Finally, engaging portions of spring clamps 24 are engaged with rear end faces of the connector plugs 23 and with stepped portions 31 of the protective member 18, so that each spring clamp 24 is bridged between a corresponding one of the connector plugs 23 and the waveguide component 1, whereby the connector plugs and the waveguide component are brought in axially urged contact with and fixed to one another.
According to the aforementioned optical waveguide component, an accurate connection between the waveguide pattern and the optical fibers can be achieved without a particular alignment operation, by simply connecting the waveguide component and the optical fiber ribbons 21 through the guide pins 19, 20 projecting from the end members 2, 3 and inserted into the through holes 22 formed in the connector plugs 23. In order to insert the guide pins 19, 20 into the through holes 22, however, the positioning of the connector plugs 23 relative to the connecting end members 2, 3 must be made precisely, and it is difficult for an operator to carry out a manual positioning operation accurately and promptly.